terraform: don't fail refresh if output doesn't exist [GH-483]

terraform/context.go

@@ -531,6 +531,14 @@ func (c *walkContext) Walk() error {
 	outputs := make(map[string]string)
 	for _, o := range conf.Outputs {
 		if err := c.computeVars(o.RawConfig, nil); err != nil {
+			// If we're refreshing, then we ignore output errors. This is
+			// properly not fully the correct behavior, but fixes a range
+			// of issues right now. As we expand test cases to find the
+			// correct behavior, this will likely be removed.
+			if c.Operation == walkRefresh {
+				continue
+			}
+
 			return err
 		}
 		vraw := o.RawConfig.Config()["value"]

terraform/context_test.go

@@ -4131,6 +4131,46 @@ func TestContextRefresh_noState(t *testing.T) {
 	}
 }
 
+func TestContextRefresh_outputPartial(t *testing.T) {
+	p := testProvider("aws")
+	m := testModule(t, "refresh-output-partial")
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		State: &State{
+			Modules: []*ModuleState{
+				&ModuleState{
+					Path: rootModulePath,
+					Resources: map[string]*ResourceState{
+						"aws_instance.foo": &ResourceState{
+							Type: "aws_instance",
+							Primary: &InstanceState{
+								ID: "foo",
+							},
+						},
+					},
+				},
+			},
+		},
+	})
+
+	p.RefreshFn = nil
+	p.RefreshReturn = nil
+
+	s, err := ctx.Refresh()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(s.String())
+	expected := strings.TrimSpace(testContextRefreshOutputPartialStr)
+	if actual != expected {
+		t.Fatalf("bad:\n\n%s\n\n%s", actual, expected)
+	}
+}
+
 func TestContextRefresh_state(t *testing.T) {
 	p := testProvider("aws")
 	m := testModule(t, "refresh-basic")
@@ -4441,6 +4481,10 @@ module.child:
     ID = new
 `
 
+const testContextRefreshOutputPartialStr = `
+<no state>
+`
+
 const testContextRefreshTaintedStr = `
 aws_instance.web: (1 tainted)
   ID = <not created>

terraform/test-fixtures/refresh-output-partial/main.tf

@@ -0,0 +1,7 @@
+resource "aws_instance" "foo" {}
+
+resource "aws_instance" "web" {}
+
+output "foo" {
+    value = "${aws_instance.web.foo}"
+}